>"your choice of vehicle brand is fungible"
I disagree wholeheartedly. One of the things Toyota has done is to establish itself as a reliable automaker of quality. People specifically think of Toyota/Honda as the vehicle makes which are most likely to last a long time and put up with abuse. Contrast this to the reputation of GM or Daewoo.
You also have the human element, where people are attracted to brand marketing and how certain models make them feel.